The preparation of the end of an optical fiber for connection to another fiber in end-to-end relation involves, in general, the stripping of the insulation from the end of the fiber and then cutting or cleaving the bared portion of the fiber to a predetermined length. As is well known in this field, the cutting or cleaving process is very important if good optical characteristics are to be maintained through the fused joint between two fiber ends. To facilitate this aspect of the process, various fiber cleaving or cutting devices have been developed and used.
U.S. Pat. No. 4,168,026 granted to HELMUT H. LUKAS et al on Sept. 18, 1979 discloses a tool for breaking an optical fiber comprising an elongate base member and an elongate top member pivotally connected at a rear end of the base member. An elongate cam member slides longitudinally of the base member and is actuated by pivoting the top member. A front pair of opposed gripping jaws are provided at the front end of the base member while a further rear pair of gripping jaws are spaced from the front jaws. A bending member is positioned between the two pairs of jaws. Pivoting of the top member towards the base member actuates the cam member which in turn first closes the front jaws and then the rear jaws. The rear jaws then pivot rearwardly to tension the fiber and then the bending member moves up to cause the fiber to bend over an arcuate top surface. Finally, a pivotally mounted scoring member in the top member is actuated to sweep a sharp edge across the fiber to initiate a crack which propagates across the fiber. This patent does not describe any means for removing insulation from the optical fiber.
U.S. Pat. No. 3,934,733 granted to EDWIN L. CHINNOCK ET AL on Jan. 27, 1976 discloses a hand tool for breaking optical fibers. The tool establishes a decreasing tensile stress across a cross section of an optical fiber which, at all points, is greater than zero but less than the threshold stress at which a mist zone forms. This is achieved by simultaneously applying a longitudinal tension to the rod and bending the rod. This patent does not disclose any mechanism for removing insulation from the optical fiber.
U.S. Pat. No. 4,017,013 granted to HAWK ET AL on Apr. 12, 1987 discloses an apparatus for severing the ends of a plurality of parallel optical fibers so that the end faces thereof are relatively flat, are substantially perpendicular to the fiber axis and are relatively co-planar. The fibers are bent over an arcuate surface and are slidably clamped between the flat surfaces of two pieces of rubbery material. The clamp is urged by a spring in such a direction that the fibers are in tension. After one fiber is scored and breaks, the clamp automatically slides along the remaining fibers until the clamping force on those fibers is sufficient to prevent further sliding. The fibers are individually severed in this manner. This patent does not disclose any mechanism for removing insulation from the optical fiber.
U.S. Pat. No. 4,036,419 granted to HENSEL ET AL on July 19, 1977 discloses a device for severing an optical fiber and comprises at least one fiber clamp for holding a portion of the fiber against an anvil, means for applying a constant force to the anvil independently of displacement of the anvil so that a preset tension is applied to the optical fiber. A knife is provided for engaging the fiber and initiating a fracture through the fiber. This patent does not disclose any mechanism for removing insulation from an optical fiber.
U.S. Pat. No. 4,154,385 granted to ADOLPH L. LEWIS on May 15, 1979 discloses a hand-held, manually operated tool for severing single filament, fiber optic cable. The tool is formed with a pair of handles which when squeezed together cause a fiber optic cable to be firmly gripped and positioned on an anvil member where it may be scored by a sharpened hard element such as a diamond point of a selectively predetermined point along the axis of the fiber optic cable. Further actuation of the tool causes the gripping members to be pivoted away from each other and thus part the fiber optic cable at the selectively predetermined point. This patent does not disclose any mechanism for removing insulation from the fiber optic cable.
U.S. Pat. No. 4,159,793 granted to BELMONTE ET AL on June 3, 1979 discloses a tool for preparing the ends of an optical fiber prior to such operations as coupling and splicing. The tool is adapted for single-handed operation and comprises a pair of manually actuated handles, first and second fiber supporting surfaces and a third fiber supporting surface between the first and second surfaces. The optical fiber is secured to the first and second surfaces by a pair of clamping members which are responsive to the squeezing of the handles. Once the optic fiber is secured to the surfaces, further squeezing of the handles produces separating rotation of a pair of jaw members to put the fiber under tensile stress. A cutting blade suspended above the third surface is released to produce a peripheral microcrack on a portion of the optical fiber lying on the third fiber supporting surface. The induced stress and curved support of the fiber act in combination to propagate the microcrack diametrically through the fiber so that an appropriate fiber end is obtained. This patent does not disclose any mechanism for removing insulation from the optical fiber cable.
U.S. Pat. No. 4,229,876 granted to JOHN S. DOTY on Oct. 28, 1980 discloses a combination fiber breaker and connector apparatus and method involving clamping an optical connector element to the optical fiber before breaking is effected and then removably securing the connector element to the breaker at a known position which is correlated to the location of a scoring blade and to the characteristics of the connector. The fiber is then clamped, bent, tensioned and scored in response to a single squeezing and releasing motion by one hand of the operator. The scoring is effected by a hard mounted tungsten carbide blade which moves in an arcuate path towards and across the tension fiber. The patent does not disclose any mechanism for removing insulation from an optical fiber.
U.S. Pat. No. 4,315,584 granted to FRIEDRICH WUESTNER on Feb. 16, 1982 discloses a method and device for cutting or breaking a plurality of optical fibers contained in a cable. The device comprises an anvil positioned between a pair of common clamps for holding the optical fibers in parallel to each other. At least one of the clamps is movable. Means is provided for applying a force to the movable clamp to provide an axial tensile force. Further means is provided for applying a vertical force to each of the optical fibers positioned on the anvil at a point on the side of the anvil opposite the movable clamp and means is positioned at the anvil for notching the fibers on the anvil for separating the fibers at the notches. This patent does not disclose any mechanism for removing insulation from the optical fiber.
HELMUT H. LUKAS Canadian Pat. No. 1,166,217 issued on Apr. 24, 1984, discloses a method and an apparatus for breaking an optical fiber which comprises two spaced members each having locating means to locate an optical fiber against longitudinal movement. The spaced members are relatively movable to increase the spacing between the locating means in the direction of the longitudinal axis of the fiber. Means is provided for scoring the fiber transversely to its length between the spaced locating means to produce a score and means for urging the spaced locating means apart to apply to the fiber, after, but not during, the scoring step, tension which is sufficient to cause a crack to propagate completely across the fiber and during the scoring step to produce in the fiber a tension of a level insufficient to cause the fiber to sever on scoring. As with the preceding patents, this patent does not disclose any means for removing insulation from an optical fiber.
Heretofore, the insulation stripping operation has been effected manually using conventional, manual insulation removing tools in the form of pliers. This operation requires care and dexterity and can be relatively time consuming. In addition, the insulation is often not stripped as neatly as it should be and/or the bared portion of the fiber is nicked which means that the process must be repeated. Thus, some skill and practice is required in order to properly and proficiently prepare an optical fiber for use. There is, therefore, a need for an apparatus which automates not only the cleaving operation but also the insulation stripping operation.